Polycarbonate resins are known to exhibit superior impact resistance, transparency, strength, flame retardancy, electrical properties and heat resistance and are widely used for electric and electrical articles including automobiles and demand therefor is increasing. However, the polycarbonate resin has disadvantages of inherently high melt viscosity, poor moldability and considerably great thickness-dependent impact resistance as well as poor chemical resistance. Accordingly, in order to solve high melt viscosity of polycarbonate, an alloy product of polycarbonate with acrylonitrile-butadiene-styrene or acrylonitrile-acrylate-styrene may be used. In order to enhance chemical resistance of polycarbonate, polycarbonate may be used in combination with a resin such as polybutylene terephthalate.
An impact resistance enhancer having a core-shell structure has been used to enhance impact resistance, chemical resistance, processability and weather resistance of thermoplastic resins. Although application thereof is currently limited to enhancement of impact resistance of polyvinyl chloride, impact resistance enhancers having a core-shell structure are gradually expanding to polycarbonate resins, alloys of polycarbonate with acrylonitrile-butadiene-styrene or acrylonitrile-acrylate-styrene and engineering plastic resins such as polycarbonate-polybutylene terephthalate resins.
European Patent No. 465,792 discloses a resin composition prepared by mixing a polymer which comprises, as a main component, a rubber acrylic monomer which improves impact resistance of polycarbonate and exhibits uniform coloring when used in combination with a pigment, with polycarbonate.
Korean Patent Laid-open No. 2004-0057069 discloses use of an acrylic impact resistance enhancer with a multilayer structure comprising a seed prepared from a vinyl aromatic monomer and a hydrophilic monomer, an alkyl acrylate-based rubber core and an alkyl methacrylate-based shell for enhancing impact resistance and coloring property of engineering plastics.
However, when an impact resistance enhancer comprising an acrylic rubber component as a core substance is used for a resin having a high refractive index such as polycarbonate, a difference in refractive index between a target matrix resin and the impact resistance enhancer is great and processed products suffer from haze or are non-transparent when injected into the processed products due to large size of several hundreds of nanometers (nm), and enhancement effect of coloring property is insufficient and improvement of coloring property is limited.